A solid-state image sensor such as a CMOS image sensor is used in a video camera or a digital still camera. A solid-state image sensor normally includes pixels arranged in a matrix pattern, having photoelectric conversion units disposed therein that generate electric charges corresponding to the amount of incident light. Solid-state image sensors known in the related art include those with a single photoelectric conversion unit disposed at each pixel and those with two or more photoelectric conversion units disposed at each pixel (see PTL1).
The electric charge generated at each photoelectric conversion unit is transferred via a transfer gate to a corresponding FD (floating diffusion) area. The electric charge is converted to a voltage depending on FD area capacitance and the converted voltage signal is then read as a photoelectric conversion signal.